The present invention is related to the field of fiber lasers.
Generation of ultrafast, high-energy, high repetition-rate laser pulses in a variety of wavelength ranges is of interest in multiple applications. For instance, multiphoton microscopy, commonly used for deep tissue brain imaging, requires sources at wavelengths where fluorophores are available. Desirable operation is achieved using an excitation source having a wavelength in either of two tissue transparency windows at approximately 1300 and 1700 nm. In other applications, such as trace gas sensing, accelerator applications, and machining applications, ultrafast, energetic near-infrared or mid-infrared sources may be required or desirable. These applications may require peak pulse powers at megawatt (MW) levels. Additionally, high repetition-rate may signify sources that emit pulses at the rates of 100 kHz or more.
A fiber laser may be realized using a gain medium that emits photons at a desired color (wavelength). Most common gain media that can be incorporated in optical fibers are realized using rare earth dopants, such as Ytterbium (in the 1000 nm range), Erbium (in the 1550 nm region), or Thulium (in the 2000 nm range). Fiber-based lasers offer tremendous opportunities and have been successfully deployed in a variety of applications.